Circuits and Systems, Inc.

Arnold S Gordon

Vyacheslav D Kats

Mark K Estes

Roman Andrejko

A weighing apparatus includes a SAW oscillator and a 'push oscillator' to force the SAW oscillator into a desired mode of operation. A SAW temperature oscillator and a thermistor are also provided. The frequency of the 'push oscillator' is made immune to temperature changes by generating it via a mixer mixing the SAW temperature oscillator with an adjustable fixed frequency oscillator. Long term stability of the SAW temperature oscillator is achieved by periodic calibration with the thermistor.

Electronic weighing apparatus utilizing surface acoustic waves using sensors operating at different frequencies, having temperature compensation, and a push oscillator

A weighing apparatus includes a base ( ) supporting a cantilevered elastic member ( ) bearing a load platform ( ). The interior of the elastic member ( ) is hollowed and is provided with first ( ) and second ( ) piezoelectric transducers mounted on respective opposed posts. The transducers are arranged substantially parallel to each other with a small gap between them and are coupled to an amplifier ( ) to form a &ldquo;delay line&rdquo; and a positive feedback loop, to form a natural oscillator.

Electronic weighing apparatus utilizing surface acoustic waves

A weighing apparatus includes a SAW oscillator and a &ldquo;push oscillator&rdquo; to force the SAW oscillator into a desired mode of operation. A SAW temperature oscillator and a thermistor are also provided. The frequency of the &ldquo;push oscillator&rdquo; is made immune to temperature changes by generating it via a mixer mixing the SAW temperature oscillator with an adjustable fixed frequency oscillator. Long term stability of the SAW temperature oscillator is achieved by periodic calibration with the thermistor.

A weighing apparatus includes a base supporting a cantilevered elastic member bearing a load platform. The interior of the elastic member is hollowed and is provided with first and second piezoelectric transducers mounted on respective opposed posts. The transducers are arranged substantially parallel to each other with a small gap between them and are coupled to an amplifier to form a &ldquo;delay line&rdquo; and a positive feedback loop, i.e. a natural oscillator. According to various aspects of the invention, one or both substrates is provided with anti-reflection structure; the transducers are sealed from moisture; an hermetically sealed temperature transducer is provided to compensate for the effects of temperature gradients; a thermal transducer channel is provided on the same substrate to measure the effects of temperature gradients and thereby compensate for temperature effects; a pair of differential transducers is arranged to measure the effects of temperature changes in the same acoustic channel in which displacement measurements are made; and a phase shift is applied to the output of the amplifier(s) to improve gain.

An electronic weighing device includes a lower base plate, an upper load bearing plate, and a load cell coupled to central portions of the upper and lower plates such that the load cell responds to weight on the bearing plate. The upper and lower plates are each notched at a central location, with the notches being offset from each other. The overlapping portions of the notches form a cavity for a central portion of the load cell, The load cell is tapered or reduced in height at opposite ends thereof so that its ends fit between a notched portion of one of the upper and lower plates and a full-thickness portion of the other of the upper and lower plates. The reduced height ends of the load cell are coupled to the upper and lower plates.

Low profile electronic weighing apparatus

A weighing apparatus includes a base supporting a cantilevered elastic member bearing a load platform. The interior of the elastic member is hollowed and is provided with first and second piezoelectric transducers mounted on respective opposed posts. The transducers are arranged substantially parallel to each other with a small gap between them and are coupled to an amplifier to form a 'delay line' and a positive feedback loop, i.e. a natural oscillator. According to various aspects of the invention, one or both substrates is provided with anti-reflection structure; the transducers are arranged on overlapping substrates to further reduce reflection; the transducers are coupled to a thermal sink to reduce the effects of thermal gradients across the transducers; two pairs of transducers are provided and arranged to provide a pair of oppositely polarized signals which doubles the accuracy of measurements and also compensates for the effects of temperature gradients; a thermal transducer channel is provided on the same substrate to measure the effects of temperature gradients and thereby compensate for temperature effects; a pair of differential transducers is arranged to measure the effects of temperature changes in the same acoustic channel in which displacement measurements are made; and a phase shift is applied to the output of the amplifier(s) to improve gain.

An electronic weighing device includes a lower electrically conductive plate, an upper electrically conductive plate, a load cell coupled to central portions of the upper and lower plates such that the load cell responds to weight on the upper plate, and a flexible, conductive band coupling the periphery of the upper plate to the periphery of the lower plate. An electronic circuit is coupled to the load cell. The circuit is provided on a board which is mounted on the lower plate close to its center. A pair of bores are provided in the lower plate extending from the circuit board to an edge of the lower plate. A pair of non-conductive rods are coupled to potentiometer on the circuit board. The non-conductive rods extend through the bores from the circuit board to the peripheral edge of the lower plate. The lower plate is provided with a shielded electrical socket which is coupled by shielded cable to the circuit board. A conductive cover is provided over the upper plate, the load cell, and the band. The weighing device provides a conductive envelope which substantially encloses the load cell and associated circuitry. Preferably the band is formed with metallic cloth tape which is applied to the edges of the upper and lower plates in a sideways-.OMEGA.-shaped configuration. The band does not interfere with the movement of the plates, yet provides an RF/EM shield around the space between the plates.

Weighing scale with EMI/RFI shielding

Desk with built in computer console

An improved weighing scale comprises a base support for a plurality of load cells, a resilient load decoupling member for each load cell, and a platform. The resilient load decoupling member allows each load cell to be decoupled from non-vertical forces, but still provides positioning and self-centering means. The load cells provide an output signal indicative of the applied weight on the platform.

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Woodmere, NY, United States of America

Arnold S Gordon